Honing machine



May 26, 1942. J. E. KI INE HONING MACHINE Filed Nov. 27, 1939 5Sheets-Sheet 2 IN VEN TOR Y ah) Z474).

y 26, 1942- J. E; KLINE HONING MACHINE Filed Nov. 27, 1939 5Sh'sets-Sheet 3 J E. KLINE HONING MACHINE Filed Nov. 27, 1939 5Sheets-Sheet 4 m M. w

J E: (2; M

' ATTORNEY5.

May 26, 1942.

J. E. KLINE HONING MACHINE 5 Sheets-Sheet 5 Filed Nov. 27, 19:59

[NVENOR I J 5? 97i 24. A TTORNE Y5.

Patented May 26, 1942 UNITED STATES PATENT OFFICE HONING momma John E.Kline, Grosse Pointe Farms, Mich., as-

signor to Micromatic Hone Corporation, Detroit, Mich., a corporation ofMichigan Application November 27, 1939, Serial No. 306,208 10 Claims.'(Cl; 51-34 This invention relates to grinding or honing machines, andespecially to mechanism for individually and collectively controllingthe abrading tools of a multiple spindle machine.

The principal object of the invention is to improve the art of grindingmachines.

It is also an object of the invention to provide control means for eachabrading tool of a multiple spindle machine for causing such tool toeffect operation for which it is set andthen to cause contraction of theabrading head of each tool upon completion of such operation.

A further object is to provide individual control means for eachabrading tool of a multiple spindle machine which renders each tooleffective until the predetermined operation for that tool has beencompleted, and then retracts all of the abrading tools when the desiredoperations have been efiected.

Another object is to provide each abrading tool of a multiple spindlemachine with a working expansion limiting means for maintaining eachtool effective until full limit expansion operation for which it hasbeen set is completed, in conjunction with control means for retractingall tools when all operations for which the tools are preset have beeneffected, and further, to provide each tool with manually adjustablepositive stop expansion limiting means effective as a safety I stop forlimiting expansion of the tool to a slightly greater amount in the eventthat the working expansion limiting means fails to operate.

Other objects, features, and advantages become apparent from thefollowing description and appended claims.

For the purpose of illustrating the genus of the invention, a typicalconcrete embodiment is depicted in the accompanying drawings, 'in'which: Figure 1 is a perspective view of a multiple spindle grindingmachine constructed in accordance with the principles of this invention;

Fig. 2 is aside elevation of one of the tool spindles which engages acentering and guiding bracket;

Fig.3 is an enlarged side elevation with parts broken away and shown insection of'the upper portion of one of the tool spindles depicted inthrough drive and control means of one of the spindles depicted in Fig.1, and associated parts being shown in elevation orin partial section;

Fig. 7 is a diagrammatic view illustrating the control system for themultiple spindle'grinding machine depicted in Fig. 1;

Fig. 8 is a central vertical section of parts shown at the lower end ofFig. 3, the section being taken at approximately right angles to thepartial section shown in Fig. '3; and,

Fig. 9 is an enlarged diagrammatic illustration of switch mechanismshown in Fig. .7.

Referring especially to Fig. 1 of the drawings, there is illustrated aworkpiece in the form of an engine block l0, having a plurality ofcylinder bores II which are to be ground, honed, or polished, suchworkpiece being indicative of any multiple cylinder block of a gasengine, steam engine, compressor, or similar apparatus adapted to beheld in stationary position on an appropriate support of the machineillustrated and by any suitable fastening means, not shown. The abradingmachine comprises an upright column I2 terminating at its upper end in amain housing l3 and having auxiliary housings l4 and I5 extendingforwardly for housing spindle drive mechanism. Journalled in areciprocating head or carriage l6 are a plurality of spindles [1, eachcomprising a driving portion 20, manually adjustable expansion stopmeans 2|, and an abrading head 22. A guiding bracket 23, preferablyintegrally built into the work holding fixture for the workpiece I0, isprovided for centering and guiding the aiorading tools into the bores IIof workpiece Ill. An hydraulic cylinder 24 is disposed between theauxiliary housings l4 and I5 for moving the reciprocating carriage orhead It toward and away from the workpiece for the purpose of moving theabrading tools into and out of the bores II of such workpiece I0.

Reference may now be had to Figs. 2 to 5 and 8, in which the numeral 25represents the body of the head portion 22 of the abrading tool and suchbody is provided with an axial bore 26, a plurality of radiallongitudinally extending grooves 21 extending through the body 25. Adouble cone expander 28 is axially movable within the bore 26 and makesa two-point contact at points 30 with stone holder 3|, each'of theholders 3| carrying a stone 32 provided with end clips'and -maintainedin assembled relation with respect to the stone holder by means of bandsor garter springs 33. The pitch of the double coneexpander is beyond theangle of reversibility, allowing the expansion mechanism to advance the=tapered orirregular bores. The upper end of the body 25 is externallythreaded and secured by means of a rocker connection to the shank 34:The rocker connection comprises a threaded sleeve 25, lock nut 36, asocket ring 31, and ball and socket portions 38 formed on shank 34 andbody 25. The upper end of the double cone 28 is connected by means of auniversal joint 48 to a spindle 4|. The rocker connection between theshank 34 and the body 25, in conjunction with the universal joint 48,permits uniform transfer of expansion pressure to the abrading tool andcompensates for slight misalignment of the work ,with relation to theaxis of the machine spindle.

Referring more especially to Figs. 3 and 8, the upper end of the spindle4| is depicted asthreadedly connected to a holder 42 for a pin 43 whichprojects through the slot 44 of the shank 34 and into an adjustingsleeve 45. The sleeve 45 is externally threaded and threadedly engages aknurled adjusting nut 46. The nut 46 supports a sleeve 41 throughanti-friction members 48. A ball 58 is biased upwardly into one of aseries of apertures inthe lower end of the sleeve 41 by springs 5|retained by studs 52 for locking the 30 anism individual to and'designedfor effecting nut 46 against accidental rotation. The antifrictionmembers 48 are maintained in position by a sleeve 53 pinned to thesleeve 41 by pins 54.

A pin 55 fixed to the sleeve 41 extends through a slot 56 provided inthe shank 34,'the gap between the pin 55 and the base portion of theslot 56 constituting the safety positive stop limiting means forregulating theexpansion of the abrading tool in the event of failure ofthe'working expansion limiting means, later described, to function. 1

The stop gap may be adjusted by rotating the knurled adjusting nut 46which, due to its threaded engagement with the adjustment sleeve 45,opens or closes the gap between the lower surface of the pin 55 and thebottom of the slot 56. Such positive stop expansion limiting means ofthe abrading tool is intended to be set slightly beyond theworking stoplimiting means, to be explained later, and to be employed only as asafety means to prevent grinding or honing-a cylindrical openingmaterially oversize. The upper bore of-the shank 34 is enlarged slightlyto provide a shoulder 51 adapted to support the lower end of a recoilspring 68, the upper end of which abuts a pin 55 to effect contractionof the abrading tool head when compression on the expanding me'an's,later described, is relaxed.

The driver 20 of the abrading tool includes a universal joint 6| and isconnected'to the upper end of the shank 34, by a pin 62 adapted to bemaintained in assembled relation with respect to unit, indicatedgenerally at 2|. A slot 81 is cut through the drive shaft push rod 66 topermit axial movement of the latter without interference with the pin62.

Referring more specifically to Figs. 3, 4, 5, and '1, the shank 34 isprovided with one, while the body 25 is provided with a plurality, oflongitudinally extended passages l8, three such passages beingillustrated in the body 25, leadingto a corresponding number of outletnozzles l3 extending radially outwardly from the approximatelylongitudinal center ofthe body 25 and spaced equidistantly about itsperiphery. These nozzles extend outwardly lesser distances thanthat ofthe normal extension of the stones 32. The passage 18 opens outwardlythrough the shank 34 .to an annular recess 23 which is arranged toregister with a similar recess 33' in a collar 49 rotatably journaled onthe shank between the driver 28' and the adjusting unit 2|. A spacercollar 58 fixed to the shank 34 between the'collar 43 and the sleeve 41of adjusting unit 2|, maintains the collar in the desired positionaxially of the tool spindle and the recesses 28 and 38 in registry. Afitting 68 .and a flexible conduit 68 lead from the registering recesses23 and'33 for purposes described hereinafter.

Reference may now be had to Figure 6, which illustrates the fluidpressure responsive mechexpansion of each abrading tool, and furtherdepicts control means for such fluid pressure responsive mechanism andthe rotating guide mechanism for each tool spindle. Each abrading toolis rotatably driven by means of a gear 18, keyed at 1| to a drive shaft12, which is journalled by means of thrust bearings 14 to thereciprocating carriage or head l6. The gears 18 are driven from spindledrive mechanism housed within the auxiliary housings I 4 and i5 of theabrading machine illustrated in Fig. 1. The gear sleeve '12 isthreadedat its lower end and clamped to the driver 28 by means of the clampingsleeve 15 which threadedly engages the lower end of the driver and shank34 by a sleeve 63 which is H the double cone expander 28 through theadjustment mechanism included in the adjusting gear sleeve 12.Cylindrical bores 16 are provided in the upper portion of thereciprocating carriage or head l6 in axial alignment with the axes ofeach of the tool spindles. A piston 11 is disposed in each of thecylinders 16 and is provided with a downwardly and axially extendingstem 18 adapted to transmit pressure from the fluid compression chamber88, which lies between the piston 11 and the closed or blind end of thecylinder 16, to the upper end of the push rod 65 for the purpose ofexpanding the abrading tool 22. Each piston stem 18 is provided withan'enlarged portion 8|, projecting through a stufllng box 82 which sealsand closes the lower end of its cyl inder 16. This arrangement alsoprovides a fluid pressure expansion chamber 83 between the smiling box82 and the lower end of the piston 11, so that when fluid pressurewithin the latter chamber exceeds that in the fiuid pressure chamber",the piston 11 will elevate and allow the recoil spring 60 (Fig. 3), tocollapse the head 22 of the abrading tool. A solenoid operated valve,

indicated generally at 84 in Fig. 6, controls the admission of fluidpressure to the compression.

chambers 86 and 83 disposed at opposite ends of each piston 11. Eachvalve 84 comprises a cylindrical casing provided with a central bore 86,which in turn is provided with five substantially equally spaced annulargrooves 81. A return passage 88 connects the extreme right and left handannular grooves 81 with each other, but

communicates with none of the other annular passages 81. A returnconduit 90 leads from the bore 88 will be in communication with eachother,

and the centrally arranged annular grooves 81 will be in communicationwith the next adjacent annular ,grooves on the first-mentioned end.

As illustrated in Fig. 6, the plunger 9| is moved to its extremeleft-hand position with the left-- -hand piston 92 closing communicationbetween 1 the adjacent grooves at the left-hand end of the bore 86, andwith the next to left-hand groove 81 in communication with the centralgrooves 81,

while the right-hand piston 92 closes the central groove 81 with respectto the next right-hand groove 81 and the latter groove isincommunication with theextreme right-hand groove 81. A conduit 93communicates with the nextto lefthand annular groove 81 and with thefluid p'ressurechamber 80 while a conduit 94 communicates with the nextto right-hand annular groove 81 and the fluid pressure chamber 83. Apressure supply conduit 95 communicates between the pressure fluidsource and the central annular groove 81. Thus, with the plunger 9| inthe position indicated, pressure fluid will flow from the conduit 95through the central annular groove 81 to the next left-hand annulargroove 81, and

through the conduit 93 to the fluid pressure chamber 80, and force thepiston 11 downwardly to expand the abrading tool. At this time, theleft-hand piston 92 cuts 'ofi communication between the left-hand groove81 and the next to left-hand groove 81, so that there will be flowbetween the pressure supply and the return line,

and the right-handpiston cuts ofi communication between the centralannular groove 81 and the next hight-hand annular groove- The latterannular groove, however, is in open communication with a right-handannulargroove 81 and the return passage 88, so that pressure chamber 83will be in communication'through the conduit 94 and the return passage84 with the return line 90. Movement of the'plunger 9| to the extreme.right-hand position will place compression chamber 83 in communicationwith the pressure supply 1 conduits 95 and the pressure chamber 80incom- -munication with return line 90. This will effect elevation ofthe piston 11 and allow the recoil spring 80, indicated in Fig. 2, tocause contraction of the head of the abrading tool.

, Solenoids 96 and 91 are provided at the right and left-hand ends,respectively, of valve 84, asindicated in Figs. 6 and 7, and in theillustrated. position, solenoid 91 is energized while solenoid I -98 isin de-energized condition and pressure supply conduit 95 is incommunication with pressure chamber 80 to effect expansion of theabrading tool. r p

The working expansion limiting means for each abrading tool iscontrolled-by. apressure T responsive means 13 and amicro switch I05.

away from the micro switch I05, is arranged rocating carriage or headI8, and. is provided with a, stem I02 which projects through a threadedadjusting plug I03, the latter being maintained in adjusted position byvirtue of its threaded engagement with the cylinder 98. The plug I03 isadapted to be adjusted to regulate the force exerted upon the plungerI00 by the spring I 0|, ,so that the latter, at the proper time,operates the micro switch I05 when the piston 11 has descended theproper amount to i effect the desired expansion of the abrading tool.

Reference may now be had to Figs. 7 and 9 which depict a control systemfor the reciprocating carriage I6 and the six abrading tool spindlescarried thereby. As indicated in Fig. 7, a micro switch I 05 is providedfor each of the tool spindles and each micro switch I05 controls theoperation of a piston 11 through a solenoid operated valve 84, but asingle piston and solenoid operated valve being illustrated. Fig. 9illustrates diagrammatically the two "left-hand micro switches I05 andthe extreme right-hand micro switch I 05 shown in Fig. 7; Each of theswitches I 05 includes a pair of stationary contacts I95 and I01 mountedon a base plate I08, and adapted to be contacted by a terminal contactIIO carried by a snap spring conductor ,I I I, which normally maintainsthe contact H0 in engagement with the stationary contact I06. The snapspring conductors III are all connected by conductors I58 to a powerline I I3 leading to a suitable source of electrical energy, not

' A plunger I00 of the pressure responsive means v .13, normally biasedby means of a spring IOI shown. Another power line II 2 leads to oneterminal of each of the solenoids and '91 of each solenoid. operatedvalve 84. The stationary contacts I06 are connected by conductors II4 tothe remaining terminals of the solenoids 91 while. the stationarycontacts I01 are connected by means of conductor II5 to the remainingterminals of solenoids 96. .A stationary contact H6 is mounted on eachswitch board I 08 of theinicro switches I05 and is adapted to be engagedby a contact I I1 carried by the snap spring conductor III when theterminal contact IIOengages the stationary contact I01.

-II1 are insulated by means o'f'dielectricpads II8 frdm the snap springconductors III; The contacts II1 of the extreme right-hand micro switchI05 is connected by means of a conductor I20 to one'terminal of thewinding or solenoid I2I, the remaining, terminals of the coil ofsolenoid I2! being connected by means of a conductor i22 to power lineH2. The stationary contacts II 6, except for that of the left-handswitch I 05, are each connected to the contacts II1 of the nextconnector switch to the left, as viewed in Figs. 7 and 9, The contact H6of the left-handmicro switch I05, as viewed in Figs. '7 and 9, isconnected by means of a connector I23 with the power line II3. Eachmicro switch I 05 is operated by a switch actuating plunger I24 providedwith two insulated pegs I25 and these plung'ers are-adapted to beactuatedloy springs I38 to snap the spring conductor III to the left, asviewed in Figs. 7 and 9, in order to break contact between the terminalcontacts I I0 and stationary contacts I08 and cause the terminal contacts H0 to engage the stationary contacts I01 and also at the same timeto cause the contacts III to engage the stationary contacts I I6.

As indicated in Fig. 7, the solenoid I2I is adapted to operate a valveI26, which controls the admission of fluid under pressure to either endof the cylinder 24 for lowering or elevating thereciprocating carriageor head I6. It is noted that the solenoid I2I is energized only whenallof the micro switches I26 have operated to snap the spring conductorsIII to the left-hand position, as viewed in Figs. 7 and 9. Suchleft-hand position is indicated by the broken line position of snapspring conductor III of the extreme lefthand' switch, as indicated inFig. 9. This closes the circuit from the power line II2, to the coil ofsolenoid I2I, conductor I20,contacts II! and H6 of all of the microswitches, and conductor I23, completing the circuit to the other powerline I I3.

Energization of the solenoid I2I causes it to opcrate the valve I26, sothat the hydrauliccylinder 24 will elevate the reciprocating carriage orhead I6 to remove the abrading tools from the workpiece and guidebracket 28. The valve I26 may be operated in the opposite direction byduit I32 leads from the pressure conduits 95 at a point between the pumpI30 and the solenoid operated valves 64 to the control valve I26 forhydraulic cylinder 24. A-return line I33 leads fromthe fiuid pressureline I32 back to the tank I3I, and a pressure regulator I34 maybe'interposed in this return line for regulating the pressure of thefluid supply to the control valve I26. A pressure regulator I35 may alsobe interposed in the pressure conduit 95 between the pump I30 and thesolenoid operated valve 64, the return conduit I36 leading from thepressure regulator I35, to'

the return conduit 90. A motor I31, or other suitable driving means, isprovided for operating the pump I30.

Air is supplied at a comparatively high but constant pressure through aconduit I40 to supply air under pressure to the pressure responsivemeans I3 and through the flexible conduit 69, fitting 66, androtatablyjournalled collar 49, to the longitudinal passage I6 in shank 34 andnozzles I9 of the passage I6 in the body 25. The air may be supplied. tothe conduits I40 by any suitable source of supply, not shown, high airpressures being employed since these are susceptible to comparativelyclose pressure regulation. A pressure reducing valve I is interposed'inthe conduit I40 and just beyondthe pressure reduction valve I4 I apressure gauge I42 is provided for indicating the reduced pressure. Avolume control valve I43 is interposed in the conduit I40 and this isfollowed by a pressure gauge I44 to indicate the pressure to whichtheair has been reduced after passing through both the pressure reducingvalve I and the volume control valve During operation of the abradingmachine, the

tool spindles "are rotated through gears 10 .and the spindle drivemechanism contained within the housing I4 and, I5. Fluid under pressure,supplied from the tank I3I by means of pump I30, acts through thecontrol valve I26, solenoid I2I being deenergized atthis time, to lowerthe spindle head I6 and lower the tool spindles I1 through the/ guidingbracket 23 to the bores II of workpiece I0. Fluid under pressure is alsosupplied from the pump I30 through the pressure conduit 95 to thesolenoid operated valves 64 and conduits 33 to the pressure chambers 60for each of the tool expanding pistons II in order to effect expansionof the abrading tool head 22. At this time, all of the micro switchesI05 are in the positions indicated in Fig. 7 and in the full linepositions indicated in Fig. 9 with the solenoids 91 energized and thesolenoid operated valves in the positions indicated in Fig. 6. Thesolenoids 91 are energized by the electrical circuit including the powerline II2, the coil of solenoid 91, conductors-H4, stationary contactsI06, terminal contacts IIO, the snap spring conductors III, andconductors I56 which lead to the power .line. I I3. Fluid pressurewithin the pressure chambers 60 forces pistons I1 downwardly until eachabrading tool head 22 has been expanded to the working limit for whichthe pressure responsive means 13 has been set. The pressure responsivemeans 13 is set by adjusting the spring tension of spring IOI by meansof the screwthreaded plug I03. 'The spring III can force the piston I00to the left, as viewed in Fig. 6, only when the air pressure suppliedthrough the conduit I40 and through the pressure reducing valve I andvolume control valve I43 drops sufllciently to permit the spring III tomove the piston I00 to the left asviewed in Fig. 6. It is noted that theair pressure supplied to the left-hand end of piston I00, asviewed inFigs. 6 and 7, is vented only at the nozzles I9 in the tool head 25. Asthe cutting stone 32 increases the diameter of the cylindrical openingin the work piece I0, the clearance increases between the ends of thenozzles I9 and the bores of the cylindrical openings of the workpiece.When such clearance has reached a predetermined value, a greater amountof air escapes through the nozzles I9, through passages I3. collar 49,fittings 66 and flexible conduit 69 than is admitted through the volumecontrol valve I43 thus causing a pressure drop upon the left-hand end ofthe piston I00, as-viewed in Figs. 6 and 7, so that the spring IOI canmove the piston III to the left and permit snapswitch I05 to operate.

In each snapswitch I05, the spring I33 causes the slide bar I24 tofollow the movement of the piston I00 of the pressure responsive means13 associated with that snapswitch. As soon as the pressure has droppedsufliciently at the left end .of piston I00 of the pressure responsivemeans I3, movement of the piston to the left will allow the springs I38of the associated snapswitch I05 to move the slide bar I24 to the left,as viewed in Fig. 9, so that a peg I 25 on the slide bar I24 will forcean intermediate portion of the snap spring conductor II I past the deadcenter of pivot centers H9 and cause the snapswitch to assume theposition indicated in broken lines. It is noted in this connection thatthe pegs I25 engage the snap spring conductors I I I at a point spacedfarther fromthe lower pivot center I I9 than from the upper pivot centerH9, as indimeans to operate said valve and reverse-the action of thetool expanding and contracting maintain the terminal contacts flrmly inengagement with the stationary contacts I06 until the snap springconductors have been-so thrown beyond dead center and throw the snapspring switches to the position indicated by broken lines at theleft-hand side of Fig. 9. When a micro switch has been operated from thefull line position to dotted line position, contact is broken betweenthe stationary contact I06 and terminal contacts IIO which severs thecircuit for the coil of solenoid 01 thus de-energizing the solenoid. Themicro switches I are operated individually switch has enlarged itsrespective work bore sufliciently to provide ,the predeterminedclearance between the nozzles I9 and the bore of the cylinder cut in theworkpiece thus causing a suflicient venting in the air pressure systemto permit the pressure responsive means 13, individual to the abradingtool, to cause its piston I00 to move sufficiently to the left so thatits associated micro switch I05 will operate. Operation of a microswitch brings the terminal'contact IIO into engagement with stationarycontacts I01 in order to energize the solenoid 90 through the powercircuit including the power line IIZ, the coil of solenoid 96,conductors II5, stationary contacts I01 snap spring conductor III, andconductor 50 to the power line II3. As soon as all of the micro switchesI25 have been thrown to the left-hand positions, broken line positionsindicated in Fig. 9, the circuit is closed between the power line H3through the conductor I23 of the extreme left-hand micro switch I05 tothe contact III which at this time engages the stationary contact II6 ofthat switch and thence through all of the'contacts III and IIS of theother switches to the conductor I20, and then through the winding of thesolenoid III to the power line IIZ. f This efiects energization ofsolenoid I2I and reverses the action of the control 1 valve I26 causingthe hydraulic cylinder 24 to ',;}.elevate the spindle head I6.vEnergization'of the solenoid 96 has in the meantime caused fluidpressure delivered fromthe pump I30 through the solenoid operated valves84 and conduit 94 to the pressure chamber 03 to elevate the piston "inorder to causecontraction of the tool heads .23 prior to theirwithdrawal from the borev II of workpiece I0. v i Asmany changes couldbe made'in the above described construction, and many apparently widely.difierent embodiments of this invention could-be, had without departingfrom the spirit and scope thereof, it is intended that all mattercontained in theabove description or shown in the accompanying drawingsshall-be interpreted as illustrativeand not in a limiting sense..What-,is claimed is: c 1. In a grinding or honing machine, incombination, a reciprocating tool support, means for reciprocating, saidsupport, a spindle journalled atone end in. said support and carryingat-its otherend an expansible and contractible abrading tool, means forrotating said tool, means for expanding and contracting the abradingtool, fluid pressure responsive means for controlling the operation ofsaid tool expanding and contracting means, avalve for reversing theaction 01' the'toolexpanding and contracting means and a source ofpressure fluid communicating as-soon as the abrading tool associatedwith each means.

2. In a grinding or honing machine, in combination, a reciprocating toolsupport, means for reciprocating said support, a spindle journalled atone end in said support and carrying at its other I end an expansibleand contractible abrading tool, means for rotating said tool, means forexpandingand contracting the abrading tool, fluid pressure responsivemeans forcontrolling the operation ofsaid tool expanding and contractingmeans, a plurality of discharge nozzles in the periphery of saidabrading tool, and a source of pressure fluid communicating with'saidwhereby a pressuredrop occurring as a result of a predetermined amountof clearance between the nozzles in the abrading tool and the bore ofthe workpiece cut by the abrading tool causes the pressure responsivemeans to limit the expanding action of the tool expanding andcontracting means.

. other end an expansible and contractible abrading tool, means forrotating said tool, means:for

with said fluid pressure responsive means and expanding and contractingthe abrading tool, fluid pressure responsive means for controllingtheoperation of said tool expanding and contracting means, a pluralityof discharge nozzles in the periphery of said abrading tool, asubstantially constant pressure' source of pressure fluid communicatingwith saidpressure responsive means and with said discharge nozzles, andpressure reducing means interposed between said source and saidpressure. responsive means whereby a predetermined pressure drop. at thenozzles causes the pressure responsive means to limit the expandingaction of the tool expanding and contracting'means.

4. In a grinding or honingmachine, in combination, a reciprocation toolsupport, means for reciprocating said support, a spindle journalled atone end in said supportand carrying at its other end an expansible andcontractible abrading tool, meansfor rotating said tool, means forexpanding and contracting the abrading tool, fluid pressure responsivemeans for controlling the operation of said 'tool expanding andcontracting means, a plurality of discharge nozzles in-the periphery ofsaid abrading tool,-a substantially constant pressure source of pressurefluid communicating with said pressure responsive means and with saiddischarge nozzles, and

a plurality of pressure reducing vmeansinter posed in series betweensaid source and said pressure responsive means, wherebya predeterminedpressure drop at the nozzlescauses the pressure responsive means tolimit the expanding action of the tool expanding and contracting means.r

'5. In a grinding or honing machine, in .com-

- bination, a reciprocation tool support, a spindle journalled at oneend in said support and adapt-1 ed to carry at its other end anexpansible and contractible abrading tool, tool adjusting means on saidsupport including expansible and contractible fluid pressure responsivemeans for expanding and contracting the-abrading tool, a

source of pressure fluid for said fluid pressure responsive means, valvemeans ,for directing pressure fluid from said source selectively intoeither pressure responsive means and with said'discharge nozzles,

end of said fluid pressure'responsive means selectively to expand orcontract the abrading tool,

a second sourcelof pressure fluid, a second pressure. responsive meanscommunicating with said second source of pressure fluid, and a ventmeans in said abrading tool communicating with said second source offluid pressure whereby a predetermined drop in the pressure applied tosaid second fluid pressure responsive means causes the operation ofsaidvalve means. 6. In a grinding or honing machine, in combination, areciprocation tool support, a spindle V .Journalled on-one end of saidsupport and adapted to carry on its other end an expansible andcontractible abrading tool, tool adjusting means on said supportincluding an expansible and convtractible fluid pressure responsivemeans for expanding and contracting the abrading tool, and

source of pressure fluid for such fluid pressure plied to said secondfluid pressure responsive means causes the latter to reverse theoperation of said valve means.

'7. In a grinding or honing machine, in combination, a reciprocatingtool support, a spindle journalled at one end on said support andadaptedto carry on its other end an expansible and and contracting 'each'abrading tool. the source of fluid pressure for all of said fluidpressure responsive means, a valve means for each of of said pressurefluid whereby a predetermined drop in the pressure applied to the saidsecond contractible abrading tool, tool adjusting means on said supportincluding a hydraulic cylinder, a piston in said cylinder, ,meansoperable by said piston for expanding and contracting the abrading tool,a source of pressure fluid for said cylinder, valve means tor directingthe pressure fluid from said source into either end of said cylinderselectively to expand or contract the abradins tool, a second source ofpressure fluid, a second pressure responsive means individual to thattool causes the said responsive means to reverse the operation of thevalve means individual to that tool. I

9. In a grinding or honing machine for finishing a plurality ofcylindrical surfaces in a workpiece, a reciprocating tool support, meansfor moving said support toward and away from the workpiece, a pluralityof spindles each journalled at one end on said support and adapted tocarry on its other end an cxpansible and contractible abrading tool, atool adjusting means on each tool on said support including expansibleand contractible fluid pressure responsive means for expanding andcontracting each abrading tool, a source of pressure fluid for all of'saidfluid pressure responsive means, a valve means for each of saidfluid pressure responsive means for directing pressure fluid from saidsource selectively into either end of each of said pressure responsivemeans to expand or contract one of the abrading tools, a second sourceof pressure fluid, a second pressure responsive means individual to eachtool and communicating with said second source of pressure fluid, ventmeans in each abrading tool communicating with the said second source ofpressure fluid whereby a prepressure responsive means communicating withsaid second source "of pressure fluid, and a vent means in said abradingtool communicating with saidsecondsource of fluid pressure whereby apredetermined drop in the pressure applied to said second fluid pressureresponsive means causes the said second pressure responsive means tooperate said valve means and cause it to reverse.

8. In a grinding or honing machine, in combination, a reciprocating toolsupport, a plurality of spindles each iournalled' at one end on saidsupport and adapted to carry on itsother end an expansible andcontractible abrading tool, a tooladiusting meansfor each tool on saidfluid pressure responsive means for expanding determined drop in thepressure applied to said second fluid pressure responsive meansindividual to that tool causes said second fluid pressure responsivemeans to produce a reversal of the operation of the valve meansindividual to ment, means for securing said tool in said spindle,

support including expansible and contractible a pressure fluid system-insaid tool including a jet which is set relative to the desired diameterto be machined, and means responsive to changes in pressure insaidsystem for indicating when the diameter has been reached.

' JOHN E.

